This invention pertains to relays and more particularly to push button operated relays. Relays of this type have generally included a push button which positively closes electrical contacts to complete an electrical circuit through the contacts. Closure of the electrical contacts also completed a circuit to the relay coil, thereby energizing the coil. Generally, in the prior art, as long as the relay coil was energized the contacts were held in, independent of the operation of the push button.
Relays of this general type are shown, for example, in U.S. Pat. Nos. 3,622,925 and 3,733,568, and are used in many appliances wherein a push to start feature is desirable, such as clothes dryers, microwave ovens, etc. However, these relays have generally included only one set of normally open contacts. Thus, the prior art push button relays were generally able to control only one function, or more than one function simultaneously, of a multifunction appliance. For example, with a prior art push button relay only the heater, the motor, or both the heater and the motor simultaneously of an electric clothes dryer could be controlled by the push to start relay.
With permanent press and other modern faabrics it has been found desirable to cycle the heater and motor on and off in accordance with a predetermined program in order to obtain the optimum drying conditions. In the prior art, the program was generally controlled by a timer motor.
However, with the increased use of electronic solid state circuitry in appliances today, it has become desirable to replace the timer motor with an electronic control unit which controls the power supplied to both the heater and the motor.